Piston cylinder apparatus



Feb. 19, 19.63 i s, J, MIQHALAK, JR Re. 25,334

PISTON CYLINDER APPARATUS original Filed March 22, 1951 INVENTOR.

San/ey Micha/ak -B United States Patent O 25,3% PISTN CYLlNDER APPARATUS Stanley J. Michalak, Sir., West iive, Mich., assigner to Mechanical Power Corporation, Grandviile, Mich., a

corporation ot Michigan Original No. 2,625,910, dated Jan. 2.0, 1953, Ser. N

216,921, Mar. 22, 1951. Application for reissue Juiy 13, 1962, Ser. No. 216,612

12 Claims. (Cl. 121-40) Matter enclosed in heavy brackets :i appears in the original patent but forms no part et this reissue specification; matter printed in itaiics indicates the additions made by reissue.

This invention relates to a novel and very useful pneumatic rod actuating apparatus, wherein a piston actuated rod may be forced outwardly at one end of a cylinder against a stop of any type whereupon, automatically within the cylinder, a lock is brought into operation which maintains the rod in its outermost position and prevents any return thereof, which, without such lock would be possible upon a pressure greater than yielding liuid pressure against a piston within the cylinder operatively connected with the rod, or upon a sucient diminution of such pressure.

With my invention, positive clamping may be obtained by the use of fluid pressure, or a preselected stopping of the pressure actuated rod obtained without variations or uncertainties because of variations in the duid pressure used. Also with my invention, a release and return of the rod to its initial position is automatically accomplished by reversing the flow of iluid pressure. vIt is an object and purpose of the present invention to provide an apparatus of the character described which is particularly effective `for the purposes for which it has been designed, sturdy and not lia-ble to get out of order, and which may be economically produced.

An understanding of the invention may be had from the following description, taken in connection with the accompanying drawing, in which,

FIG. 1 is a longitudinal vertical section through the piston cylinder apparatus of my invention, with the piston at substantially one extreme of its movement.

FIG. 2 is a similar section showing the piston in another position, substantially at the opposite extreme or" its movement.

FIG. 3 is a horizontal vertical section substantially on the plane of line 3-3 of FIG. 2 and FIG. 4 is an enlarged elevation of the split locking nut which is automatically moved to operative position upon the outward movement of the piston rod to a predetermined position.

Like reference characters refer to like parts in the different tgures of the drawing.

A cylinder 1, shown horizontally located, is closed at one end by a circular plate 2 and at the other end by a head 3. Pipes indicated at 4 and 5 connected with the parts 2 and 3, respectively, are for the conduction into and exhaust out of the cylinder at opposite ends thereof of fluid pressure, said pipes being adapted to carry a pressure Huid which in practice, preferably, will be cornpressed air.

A rod 6 extends centrally through the head 3 and at its inner end portion is axially bored for a distance into which the free end portion of an axially located rod 7 extends and is guided. The rod 7 is securely connected to the cylinder closure 2, extends the full length of the cylinder and beyond the outer side of the head 3 and, for the major portion of its length from its free end toward but short of its opposite end, is formed with a consecutive series of annular grooves 8, producing serrated annular ribs preferably, of the type and form best shown in FIG. 2. The rod 6 at its incr end is equipped with a head 9.

"ice

Around the rod between said head 9 and the head 3 a piston 16 is located, sufficiently loose upon the rod that it may have a relative movement with respect thereto, Ifrom a position as in FIG. 1 against the head 9 to other positions, one shown in FIG. 2, away from said head. The piston in practice is made of two back to back cup leathers, the outer anges of which bear against the inner sides of the cylinder 1, while the web portions or bottoms of such cup leathers, at the central opening therein through which the rod 6 passes, are snug against the rod, the piston permitting substantially no passage of compressed air from one side thereof to the other.

At what may be termed the inner side of the piston, a housing of sheet or flat metal is permanently secured. It comprises three sections, a larger diameter section 11 ilanged at its free end for screws to pass through the piston and through said flange to connect the housing to the piston, an intermediate conical section 12 and an inner end section 13 of circular cross section of lesser diameter which, at its free end, is provided with an inturned annular flange against which one end of a flat wire coiled compression spring 1=4 seats. The rod 7 passes through the described housing and is surrounded at its grooved portion 8 by the spring 14, which is a compression spring of relatively heavy strength.

The opposite end of the spring 14 bears against a split or divided nut having two half circular segments 15, the adjacent ends of which when together provide a substantially circular ring, but which are normally separated from each other. Rods 16 as shown in FIG. 4 extend from the end portions of one of the parts 15 to the adjacent end portions of theA other part with coiled compression springs 17 of light strength around the rods which, when free to do so, separate the two parts 15 from each other as in FIG. 4. The exterior diameter of the divided nut,

when the two parts are brought together, is substantially the same as the interior diameter of the section 13 of the housing described, so that when located in such section 13, the two parts o-f the nut 15 lare forced toward each other, compressing the springs 17 and engaging the grooves 8 on the rods 7, the interior opening through the split nut being grooved complementary to the grooves '8. Therefore, when the nut isin the described position shown in FIG. 2, it has a holding or locking engagement therewith. v

Between the outer side of the head 1 and the adjacent side of the parts 15 of the split or divided nut a plurality of balls 18 are located. The head 9 and the adjacent side of the parts 15', at their outer por-tions, diverge from each other as shown.

With the parts as shown in FIG. l, the two parts 15 of the split nut are separated by the springs 17, and the balls 18 are forced outwardly so as to bear against the inner sides of the section 11 of the housing. On introducing compressed air or an equivalent pressure iiuid through the pipe 4, and upon rod 6 encountering a force greater than the compressive strength of spring I4, the pressure will force the piston 10 from the position shown in `FIG. l toward that shown in FIG. 2 the piston moving away from the head 9 and moving the housing with it. The split nut l5 and balls Z8, [bein-g] which are held between the head 9 on the -rod 6 and the parts 15 of the split nut, will move relatively to the housing so as to engage against the conical section 12, and will be forced inwardly toward each other until the smaller diameter section 13 is reached, whereupon the parts 15 will be forced toward each other, overcoming springs 17 when said parts enter the section 13 of the housing and bringing the serrated teeth at the sides of the opening through the nut into tirm connection with the serrated grooves 8 on the rod 7.

During this movement the rod 6 will be moved outwardly unit it is stopped either at a preselected outer 3 position or until it comes up against material which is to be clamped between the outer end of the rod and abutment. Thereupon, the piston and the housing will continue movement until the nut parts 15 engage with the teeth and grooves 8 of the rod 7.

This engagement occurs while the balls I8 are still in rolling engagement with the conical section 12 and thus before they enter the section 13. The pressure in the cylinder, being greater than theY compressive strength of spring 14, continues to mofve piston and the housing to the position of FIG. 2. Daring this movement, the balls 18 are forced like a wedge between the leveled com surfaces of head 9 and split nut I5 andr in so doing, by reason of the mechanical'advantage obtained thereby, a greater force is exerted on rod` 6 than what normally would be transmitted to rod 6 solely by piston J0 if the piston and rod were attacheddirectly to each other.

The compressed air or other fluid pressure will maintain the parts in the position shown in FIG. 2, and it `is apparent that with said parts 15- of the nut, held against outward movement, and with the balls 18 between them and the head 9, any stopping of the rod 6,` regardlessV of pressure against it tending to return it, will be withstood until the compressed airI pressure against the piston is reduced to less than the expansivek force of the spring 14. Thus any clamping or other pressure of the rod 6 against` what [isl it may be pressed will notvary, should compressed air pressure through the pipe 4- into the cylinder change in amount. i

On releasing or exhausting the air, controlledv by a suitable valve connected with the, pipeVv Lv and., the pressure bcingreducedaround the housing and4v against the adjacent side of the piston to, atmospheric pressure, spring, 1,4 returns the piston andk housing to the position relative` to the head9 inEIG. 1,. Either 'by manual pressure against the outer end of the rod, or by fluidvpres'sureintroduced into the cylinder through the pipev 5, thepiston maybe moved back in the cylinder, carrying rod; 6 'with it, to the initial position shown in FIG. 1;.

The apparatus described mounted, upon, a` suitable base support, may be usedto clamp an articley between a clamping head` at the outer end of therod 6 and anv abutment. The rod 6 will be movedl out rapidly untilthearticleto be clamped,- located against such abutmentis engaged, bya clamping head on suchrrodi 6, after which, leaving the pneumaticpressurey on throughthepipe` 4, thcclarnp will be locked with the parts: 15 shown in they position in FIG. 2. The release is by exhausting the iluid pressureithrough the pipe 4, and the return is by moving they rod 6 hack either by hand or by pneumatic pressure throughV the pipe `5. Also such device may be used in drilling holes in materialto either preselected depths, or through material, stopping the drill very shortly after they havey passed through such material. In such case the rod 6 through cooperating stops on it and on an affixed stop means, against which the cooperating stops come, will be stopped at a predetermined position and may have secured to it at its outer end portion, au drill head or; unit movable with it, and therefore stoppedywhen the drill has penetrated a preselected desired amount;

There. are many other uses to which the apparatus may be put, which will occur to those skilled lin the art, and the invention is to comprehend all forms of structure accomplishing thesame results, however used, by substantiallythe same means, using structure withinthe scope of the claims appended, which deine the invention.

[claim:

l. In a structure as described, a cylinder, end members closing the ends of the cylinder, a rod slidably mounted and passing through one of. said ends of thecylinder, having a head at its inner end, meansy for conducting huid pressure into the cylinderfat its opposite end, a piston on said rod mounted thereon for movement lengthwise of the rod from said head to a position away fromthe head, u iixed rod secured. to the` other end of the! cylinder :[pistonfl, said rst mentioned rod having an axial boring therein into which said iixed rod extends and is guided, a housing secured to said piston at a side thereof, located around said xed rod and around the head of the rst mentioned rod, a member within said housing, said fixed rod and said member having interengaging means for connecting them together against movement with respect to each `other in one position of said member, means normally maintaining said member out of engagement with said xed rod, and mean-s automatically operated by movement of said housing when said piston is moved away from the head on the rst rod to connect said member with said fixed rod.

2. In a structure as described, a cylinder, ends closing the ends of the cylinder, a rod slidably passing through one end closure of the cylinder and at its inner end having a head, said rod from its inner end having an axial elongated boring, a xed rod permanently secured to the opposite end of the cylinder extending into said boring in the first rod, a piston on said first rod adapted, in one position, to come against said head on thev first rodv and 'mounted on the rod for movement away from Said head,

means mounted adjacent said xed rod disengaged therefrom when said piston and head on said rst rod are against each other, said means bearing against said head to move said first rod longitudinally when free of the second rod, and adapted to be moved into xed engagement therewith, and means connected to said piston, movable with it, engaging against and operating said lirst mentioned meansV into fixed engagement with said lixed rod when said piston is moved away from said head thereby fixing said means against movement to move said rst mentioned rod longitudinally.

3. In a structure; asdescribed, a cylinder, end closures for the ends of the cylinder, a rod having an axial boring from` its inner end lengthwise thereof slidably passing through one end closure of the cylinder, said rod at its inner end having ahead, a piston on said rod` movable lengthwise thereof from a position against said head to a position away therefrom, a housing secured to one side of the piston surrounding said head and extending toward the end of the cylinder to which the fixed rod is secured, said rod being telescopically received in the boring of the first rod and from its free` end for the. major portion of its length;` having a consecutive series of closely spaced projections thereon, a split, plural part nut surrounding said fixed rod located within the housing, spring means acting to normally separate the parts of the split nut and ydisengagey it from said projections on the xcd rod, said nut surrounding the iixed rod and at its inner side having projections adapted to engage the projections on the xed rod,V a compression spring between said nut and theouter end of the housing, and a series of balls lbetween the outer side of said head and the adjacent side of said split nut, said housing having its greatest cross section at and adjacent the piston in which it isA connected, and having a decreaseddiameter away therefrom, such decreased diameter of the housing being substantially equal interi-orly to the exterior diameter of the split nut when it is in engagernentl with the projections on said fixed rod.

4. A structure as `delined in claim 3, said housing having a cylindrical section of largest diameter at the end thereofv connected with the piston, an intermediate section having a progressively `decreasing diameter from said rst section, and an opposite end cylindrical section farthest away from said piston, the interior diameter of said last section being substantially equal to the exterior diameter of the split nut when closed and engaged with the xed rod.

5. A structure as dened dn claim 3, the adjacent sides of the head and split nutconverging inwardly toward each other and: against which converging sides said balls are adapted to bear, and means for introducing-and exhausting a pressure Huid into the cylinder at opposite. ends thereof. l y

6. In `a structure as described, a cylinder, end closures -for the ends of the cylinder, a rod having a head at its inner end slidably passing through one end closure of the cylinder, said rod from its inner end, and beyond the end of the cylinder through which it passes, having an axial boring, a fixed rod secured to the other end closure of the cylinder telescopically received within said boring and extending through the end of the cylinder through which said first rod passes, said rod from its free end for the major portion of its length having a plurality of successive closely spaced grooves and alternate [teeth therearound, a piston on the first mentioned rod movable lengthwise 'thereof adapted in one position to engage against said head, `a Ihollow housing secured to said piston, surrounding said head and extending toward the end of the cylinder to which the fixed rod is secured, said housing being of a larger diameter where attached to the piston than at its opposite end, a split nut comprising a plurality of connected parts surrounding said r-od and located within the housing, spring means normally separating said parts of the split nut from each other, said parts of the nut around said rod having grooves and teeth therein similar to those around said rod, a coiled compression spring between said `split nut and the outer end of the housing, and a series of balls within the housing between the outer side of said head and the adjacent side of said split nut.

7. A structure as defined in claim 6, and a conduit for carrying and exhausting compressed air into the cylinder at the side of the piston at which lthe housing is located, the interior diameter of the larger end portion of said housing being greater than the exterior diameter of said nut when the parts thereof are separated, and the interior diameter ofthe free end portion of said housing being substantiall-y equal to the exterior diameter of said split nut when the parts thereof are together, adjacent sides of said head and said parts of the fixed nut converging inwardly toward each other and against which side said balls are located.

8. In a structure as described, a cylinder having end closures, a rod slidably passing through one end closure of the cylinder, said rod being axially lbored from its inner end lengthwise thereof, a fixed rod secured to the opposite end of the cylinder telescopically received in the first rod, a piston in said cylinder movable lengthwise of and upon the first rod, means limiting the move ment of the piston toward the inner end of said first rod, means for entering pressure ui-d a-t the end of the cylinder to which the fixed rod is connected to move said piston, means connected to said piston operatively engaging the inner end of said first rod to move said rod outwardly on entrance of pressure uid into the cylinder, said last men-tioned means including a yielding coiled compression spring which is compressed in length upon resistance being encountered to outward movement by the first rod, whereupon said piston will move lengthwise of said first rod away from the inner end thereof, and means operated by said last mentioned means and yactuated thereby to connect it with said fixed rod after said piston has moved lengthwise of the first rod a predetermined distance locking said first rod moving means against movement.

9. In d structure 'as described, n cylinder, end members closing the ends of the cylinder; a rod slidably mounted und passing through one of scid ends olf the cylinder, hoving a head tzt its inner end, means for conducting fluid pressure into the cylinder at its opposite end, a piston on said rod mounted thereon for movement lengthwise of the rod from said head to u position away from the head, a fixed rod secured to the other end of the cylinder, said first mentioned rod having an axial boring therein into which said fixed rod extends and is guided, a housing secured to said piston at o side thereof, located around seid fixed rod and around the head of the first mentioned rod, a member within said housing, said fixed rod and said member having z'nterengaging means for connecting them together against movement with respect to each other in one position of said member, means normally maintaining said member out of engagement with said fixed rod, and medns automatically operated by movement of said housing when said piston is moved away from: the head on the first rod to connect said member with said fixed rod providing d stopmeans; and mechanical advantage means cooperating with said stop means, head, and said piston and housing for creating a greater force on said first mentioned rod than would normally be created solely by said piston if said piston und rod were directly attached to each other.

J0. In d structure as described, a cylinder, end members closing the ends oif the cylinder, a rod slidably mounted dnd passing through one of said ends of the cylinder, hdving u head at its inner end, means for conducting fluid pressure into the cylinder at its opposite end, a piston on said rod mounted thereon for movement lengthwise of the rod from said head to a position away fromI the head, d fixed rod secured to the other end of the cylinder, said first mentioned rod having an axial boring therein into which said fixed rod extends and is guided, a housing secured to said piston at a side thereof, located around said fixed rod and nround the head of the first mentioned rod, a member within said housing, said fixed rod 'and said member having interengoging means for connecting them together against movement with respect to each other in one position of said member, means normally maintaining said member out of engagement with said fixed rod, and means automatically operated by movement of said housing when said piston is moved away from the head on the first rod to connect said member with said xed rod providing a stop means; and o mechanical advantage wedging means located between said stop means and said head and actuated by the movement of said piston for forcing sdid head dwcy from said stop means thereby creating a greater force on said first mentioned rod than would normally be created solely by said piston if said piston and rod were directly attached to each other.

11. The device of claim 10 in which the wedging means comprises diverging surfaces one operatively associated with the head and the other operatively associated with the stop means; and d plurality of rolling elements riding on said surfaces; and means for forcing said rolling elements between said surfaces in response to movement of said piston thereby forcing said stop means und first mentioned rod apart,

I2. The device of claim 10 in which the wedging meulis comprises diverging surfaces one operatively associated with the head and the other operatively associated with the stop means; and d plurality of rolling elements riding on said surfaces; dnd an elongated cum surface inside said housing and engaging said rolling elements for forcing said rolling elements between said surfdces in response to movement of said piston thereby forcing said stop means und first mentioned rod apart.

References Cited in the file of this patent or the original patent UNITED STATES PATENTS 707,015 Ridgway Aug. 12, 1902 2,540,578 Hall et al. Feb. 6, 1951 2,632,425 Grover Mar. 24, 1953 FOREIGN PATENTS 211,847 Germany July 13, 1909 

